The bright long-lived Type II SN 2021irp powered by aspherical circumstellar material interaction

Context. Some core-collapse supernovae (CCSNe) are too luminous and radiate too much total energy to be powered by the release of thermal energy from the ejecta and radioactive-decay energy from the synthesised 56 Ni/ 56 Co. A source of additional power is the interaction between the supernova (SN) ejecta and the massive circumstellar material (CSM). This is an important power source in Type IIn SNe, which show narrow spectral lines arising from the unshocked CSM, but not all interacting SNe show such narrow lines. Aims. We present photometric and spectroscopic observations of the hydrogen-rich SN 2021irp, which is both luminous, with M o < −19.4 mag, and long-lived, remaining brighter than M o = −18 mag for ∼250 d. We show that an additional energy source is required to power such a SN, and we determine the nature of the source. We also investigate the properties of the pre-existing and newly formed dust associated with the SN. Methods. Photometric observations show that the luminosity of the SN is an order of magnitude higher than typical Type II SNe and persists for much longer. We detect an infrared excess attributed to dust emission. Spectra show multi-component line profiles, an Fe II pseudo-continuum, and a lack of absorption lines, all typical features of Type IIn SNe. We detect a narrow (< 85 kms −1 ) P Cygni profile associated with the unshocked CSM. An asymmetry in emission line profiles indicates dust formation occurring from 250–300 d. Analysis of the SN blackbody radius evolution indicates asymmetry in the shape of the emitting region. Results. We identify the main power source of SN 2021irp as extensive interaction with a massive CSM, and that this CSM is distributed asymmetrically around the progenitor star. The infrared excess is explained with emission from newly formed dust although there is also some evidence of an IR echo from pre-existing dust at early times.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-09-15
DOI
https://doi.org/10.1051/0004-6361/202553792
Citations
2
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
2.31

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article

The bright long-lived Type II SN 2021irp powered by aspherical circumstellar material interaction

M. Fraser, P. J. Pessi, A. Pastorello, Miho Kawabata et al.
2 citations
Astronomy and Astrophysics
Gamma-ray bursts and supernovae
2.31
article

The bright long-lived Type II SN 2021irp powered by aspherical circumstellar material interaction

M. Fraser, P. J. Pessi, A. Pastorello, Miho Kawabata, T. Nagao, Yongzhi Cai, J. P. U. Fynbo, Kenta Taguchi, M. Yamanaka, S. Mattila, A. Reguitti, T. Kravtsov, S. Moran, R. Kotak, Tim Reynolds, T. Kangas, P. Lundqvist, Keiichi Maeda, H. Kuncarayakti, C. P. Gutiérrez, Rashmi Gottumukkala, N. Elias–Rosa, K. Matilainen
article en
2 citations

Abstract

Context. Some core-collapse supernovae (CCSNe) are too luminous and radiate too much total energy to be powered by the release of thermal energy from the ejecta and radioactive-decay energy from the synthesised 56 Ni/ 56 Co. A source of additional power is the interaction between the supernova (SN) ejecta and the massive circumstellar material (CSM). This is an important power source in Type IIn SNe, which show narrow spectral lines arising from the unshocked CSM, but not all interacting SNe show such narrow lines. Aims. We present photometric and spectroscopic observations of the hydrogen-rich SN 2021irp, which is both luminous, with M o < −19.4 mag, and long-lived, remaining brighter than M o = −18 mag for ∼250 d. We show that an additional energy source is required to power such a SN, and we determine the nature of the source. We also investigate the properties of the pre-existing and newly formed dust associated with the SN. Methods. Photometric observations show that the luminosity of the SN is an order of magnitude higher than typical Type II SNe and persists for much longer. We detect an infrared excess attributed to dust emission. Spectra show multi-component line profiles, an Fe II pseudo-continuum, and a lack of absorption lines, all typical features of Type IIn SNe. We detect a narrow (< 85 kms −1 ) P Cygni profile associated with the unshocked CSM. An asymmetry in emission line profiles indicates dust formation occurring from 250–300 d. Analysis of the SN blackbody radius evolution indicates asymmetry in the shape of the emitting region. Results. We identify the main power source of SN 2021irp as extensive interaction with a massive CSM, and that this CSM is distributed asymmetrically around the progenitor star. The infrared excess is explained with emission from newly formed dust although there is also some evidence of an IR echo from pre-existing dust at early times.

Astronomy and AstrophysicsVol. 702
Kagoshima University (JP), University of Copenhagen (DK), University of Turku (FI), Turku Centre for Computer Science (FI), Yunnan University (CN), Chinese Academy of Sciences (CN), European University Cyprus (CY), Kyoto University (JP), Yunnan Observatories (CN), Brera Astronomical Observatory (IT), Institut d'Estudis Espacials de Catalunya (ES), Institute of Space Sciences (ES), DAWN Center for Independent Living (US), AlbaNova (SE), Osservatorio Astronomico di Padova (IT), Aalto University (FI)
National Science Foundation, Smithsonian Institution, U.S. Department of Energy, National Aeronautics and Space Administration, Alfred P. Sloan Foundation, Gordon and Betty Moore Foundation, Yale University, Carnegie Institution of Washington, Vanderbilt University, Ohio State University, California Institute of Technology, Aarhus Universitet, University of Utah, University of Washington, Johns Hopkins University, Carnegie Mellon University, University of Notre Dame, University of Portsmouth, New Mexico State University, Space Telescope Science Institute, Carnegie Institution for Science, York University, University of Oxford, European Commission, University of Edinburgh, Queen's University Belfast, Durham University, National Research Foundation, Science Foundation Ireland, Danmarks Grundforskningsfond, National Natural Science Foundation of China, Suomalainen Tiedeakatemia, Generalitat de Catalunya, Queen's University, Ministério da Ciência, Tecnologia e Inovação, Magnus Ehrnroothin Säätiö, European Southern Observatory, Ministerio de Ciencia e Innovación, National Central University, Universitetet i Oslo, Háskóli Íslands, Turun Yliopisto, Universidad Nacional Autónoma de México, National Astronomical Observatory of Japan, Stockholms Universitet, Eötvös Loránd Tudományegyetem, Max-Planck-Institut für Astrophysik, Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Canarias, Office of Science, Jet Propulsion Laboratory, University of Colorado Boulder, Smithsonian Astrophysical Observatory, Science Mission Directorate, Leibniz-Gemeinschaft, Japan Society for the Promotion of Science, Agencia Estatal de Investigación, Planetary Science Division, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory
Openalex Percentile: Top 10%
Gamma-ray bursts and supernovae
2.31
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